The Centre’s air quality panel for Delhi-NCR Monday invoked restrictive measures under stage three of the Graded Response Action Plan (GRAP) amid a sharp dip in air quality due to unfavourable meteorological conditions. GRAP III is enforced when AQI is between 401 and 450.

Stage III also entails a ban on non-essential diesel-operated medium goods vehicles with Bharat Stage IV (BS-IV ) or older standards within Delhi. BS IV is a set of emission norms for vehicles in India that came into effect in 2017. Non-essential diesel light commercial vehicles of BS-IV or older standards, registered outside Delhi, are also not allowed to enter the city.